How to prevent perforation during root canal access cavity preparation

[abdullahzubair109]

I am from Bangladesh. Seeking some expert opinions. I recently started clinical classes. Yesterday while I was trying to locate distal canal orifice on 36(lower left 6th molar ), i accidentally perforated crown (distolingually). How do you avoid these situations?? here in Bangladesh we hardly use endomicroscopes or loupes (due to socioeconomic condition). Any constructive opinion would be highly appreciated.

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[cmsmith85]

I am from Bangladesh. Seeking some expert opinions. I recently started clinical classes. Yesterday while I was trying to locate distal canal orifice on 36(lower left 6th molar ), i accidentally perforated crown (distolingually). How do you avoid these situations?? here in Bangladesh we hardly use endomicroscopes or loupes (due to socioeconomic condition). Any constructive opinion would be highly appreciated.

Lower posterior teeth are usually lingually inclined and so you need to tilt your handpiece accordingly in order to avoid perfing the tooth. Since you perforated the tooth towards the lingual, that means you had your handpiece tilted towards the buccal instead of towards the lingual. I'll try adding a picture later on to illustrate what I'm trying to say.

 

[frozenicecreamDMD]

I am from Bangladesh. Seeking some expert opinions. I recently started clinical classes. Yesterday while I was trying to locate distal canal orifice on 36(lower left 6th molar ), i accidentally perforated crown (distolingually). How do you avoid these situations?? here in Bangladesh we hardly use endomicroscopes or loupes (due to socioeconomic condition). Any constructive opinion would be highly appreciated.

you answer your own questions. you have to have to have loupes....I can see just okay with 4x loupes I can't imagine doing endo without any loupes.

If this is the case you should find the biggest canal first in the tooth and trace back to other canals --- for molars find palatal/distal canals, take some check xray as you go if you think you are there but no canals appears - use endoZ bur as round bur its hard to control the access widening.

another trick is to calibrate your xray to measure distance between canals - you can put a round bur of known size in front of the tooth and take an xray there and measure the distance between canals mesial distally and start tracing.

 

[Saddleshoes]

How do you avoid these situations??

Know tooth anatomy.

 

[oralcare123]

You don't need loupes. You need to know the location of canal orifices by learning anatomy. You shouldn't just randomly remove tooth structure searching for it somewhere. Know the depth, where pulp floor expected to be. Pay attention to the orientation of the bur relating to the long axis of the tooth

 

[abdullahzubair109]

You don't need loupes. You need to know the location of canal orifices by learning anatomy. You shouldn't just randomly remove tooth structure searching for it somewhere. Know the depth, where pulp floor expected to be. Pay attention to the orientation of the bur relating to the long axis of the tooth

can you recommend some quick resources to visualize orifice anatomy more efficiently.. I find traditional textbooks to be a little bit boring.

 

[abdullahzubair109]

Know tooth anatomy.

thanks, i will try to enrich my knowledge.

 

[abdullahzubair109]

Lower posterior teeth are usually lingually inclined and so you need to tilt your handpiece accordingly in order to avoid perfing the tooth. Since you perforated the tooth towards the lingual, that means you had your handpiece tilted towards the buccal instead of towards the lingual. I'll try adding a picture later on to illustrate what I'm trying to say.

next time i will keep it in mind. thanks for the tip.

 

[oralcare123]

 

[oralcare123]

Just Google

 

[abdullahzubair109]

Just Google

View attachment 332385

thnks

 

[Molar Whisperer]

To minimize perforating the pulpal floor on any molars, the magic number is 7 mm (use perio probe) depth of your access (not including any alterations of coronal anatomy such as crown restorations, severe occlusal attrition, etc.) All the above posters are spot on. Key to minimizing iatrogenic events is case selection. I refer a lot of cases I can't finish in less than 1 hour such as obliterated canal(s), bi/trifurcated roots, C-shaped roots, Maxillary MB root apex with PARL (PeriApical RadioLucency), any atypical anatomic variations not in the textbooks or Google.

In the US where we have an oversupply of hungry lawyers (I was in a deposition with the opposing attorney), I always document "Under microscopic magnification of 8x and 12x, no internal caries, resorption, fracture detected, all canals located and instrumented, all pulpal tissue removed."

 

[TanMan]

Flatten the tooth parallel to the occlusal plane so you don't lose your orientation and when widening your access, use a non-end cutting bur so that you can't perf the tooth. Use a 557 until you feel a drop, then widen with your non-end cutting bur such as a 7653 finishing bur. That bur will take you to each orifice w/ minimal risk of perf. Otherwise, if you perf, get acquainted with the use of Bioceramic/MTA/Geristore.